t ^7 ] 
fix inches of it red-hot. The battery in thefe expe- 
riments was in the houfe, and the wires of which 
the circuit confifted were conveyed by filken firings 
into a garden adjoining to the houfe. 
Mentioning this lofs of force occafioned by the 
length of the circuit in eledlrical explofions to Dr. 
Franklin, he told me that the fame obfervations had 
occurred to him, and that he had alfo been difap- 
pointed in an attempt to fire gunpowder at a diftance 
from his battery. 
Struck with this appearance, I endeavoured to af- 
certain the quantity of this obflrudlion, by trying 
what other courfes the eledtric fire would chufe pre- 
ferably to a long metallic circuit. In the firfl place, 
taking about a yard of the fmall brafs wire, mention- 
ed above, I difpofed it in the manner defcribed be- 
low, connedling one of the ends with the outfide of 
the battery, and the other with the infide. In the 
frfl place, I brought the parts a and b (near the two 
extremities) into contadl, and, upon the difcharge, 
found there had been a fufion in that place, and that 
a great part of the fire had taken the fhorter circuit, 
though it had been obliged to quit the wire in one 
place, and enter it again in another. Afterwards I 
removed the parts a and b X.Q fmall diflance from 
one another, and, upon the explofion, obferved a 
flrong fpark pafs between them. Removing them to 
greater and greater diflances, I found the explofion to 
pafs above one third of an inch in the air, rather than 
make the circuit of the continued wire. Ufing a 
longer and fmaller iron wire, the paffage through the 
air exceeded half an inch. I then took four or five 
yards of iron wire one tenth of an inch thick, when 
K 2 the 
